Vane retaining device



Feb. 3, 1959 w. H. BROWN VANE RETAINING DEVICE Filed Aug. 20, 1956 INVENTOR WILL/AM H BROWN 3; M 0

-ATTORNEV W v w.

United States Patent VANE RETAINING DEVICE William H. Brown, Manchester, Conn., assignor'to United Aircraft Corporation, East- Hartford, Conn., a corporation of Delaware Application August 20, 1956, Serial No. 604,940 7 Claims. (Cl. 253-78) This invention relates to axial flow compressors and turbines and more particularly to an attachment for the end of a stator vane within the supporting structure.

One feature of the invention is an attachment which will serve to damp vibrations in the vane and which will hold the vanes securely in position radially within the supporting structure. Another feature is an arrangement by which to prevent wear on the vane end or on the supporting structure as a result of vibration between or relative movement of the parts. One feature is the attachment of the vane without brazing or welding since in some cases the alloys in the vane end supporting structure cannot readily be welded or brazed.

One particular feature is an attachment by which the natural frequency of the vane assembly may be raised or lowered to place the vibrational frequency of the assembly outside of the engine operating range.

One feature of the invention is the combination of this type of attachment at the inner end of the vane with an outer end attachment that includes a foot integral with the vane and overlying and attached to the outer shroud at spaced points as by welding or riveting.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the invention.

Fig. 1 is a fragmentary sectional view through a stator showing the attachment of the vanes to the inner and outer shrouds.

Fig. 2 is an end view partly in section looking in the direction of the arrow 2 of Fig. 1.

Fig. 3 is a fragmentary sectional view along the line 3-3 of Fig. l.

Fig. 4 is a fragmentary sectional view of the inner end of the vane.

- Fig. 5 is a perspective view of a spring pin.

The vane assembly shown is adapted for use in an axial flow compressor which might be used, for example, in a gas turbine of the type shown in the Savin Patent No. 2,747,367. As shown, the assembly includes an outer shroud ring 2 and an inner shroud ring 4 arranged in concentric relation to each other and with a plurality of vanes 6 extending between the two rings. The outer end of each vane may be secured in the outer shroud ring by any suitable attachment. The arrangement shown is described and claimed in detail in the co-pending ap plication of Broders, Serial No. 604,921, filed August 20, 1956. For the purpose of this invention, the outer end of the vane 6 has a foot 8 thereon which is larger than the opening 10 in the shroud ring through which the vane projects. The foot 8 may be rigidly attached as by riveting or by welding at spaced points 11 to the outer surface of the outer shroud ring and the foot is preferably of such an arrangement as to effectively prevent circumferential tipping of the vane within the supporting structure.

The inner end of each vane 6 has as an integral part thereof an approximately oval shaped foot 12 which projects through a similarly shaped opening 14 extending '2 substantially radially through the inner shroud ring. In the arrangement shown, both the foot 12 and the opening 14 have opposite parallel sides 16 connected by rounded end portions 18, as best shown in Fig. 2. The inner shroud ring is relatively thick in radial dimension and, is provided with axially extending transverse cylindrical openings 20, Fig. 4, one-half of each of which is in the shroud ring and the other half of which is in the vane foot. These bores extend parallel to the wall .surfaces 16 and the axis of the bores lies in the plane of these wall surfaces. The bores 20 extend transversely between opposite side walls of the shroud ring. In efiect, the side walls of the vane foot have semi-circular grooves therein and the parallel walls of the opening 14 have cooperating semi-circular grooves which together form "ice the'centeral portion of'the openings 20, the 'end portions: of which are located wholly in the inner shroud ring as best shownin Fig. 2.

- g The spring pin, as best shown in Fig. 5, is in the form.

of a hollow cylindrical sleeve 22 of resilient material having an axially extending slot 24 therethrough by which to obtain .the resilient attachment. By varying the spring rate of the pin, as by varying the thickness of the sleeve or the resilience of the material making up the sleeve, it is possible to establish the desired holding action to keep the vane in position and also to damp such vibrations as may develop therein. Furthermore, if excessive vibrations occur by reason of the fact that the natural vibrational frequency of the assembly is within the engine operating range, the spring pins may be replaced by other spring pins of a difierent spring rate so as to shift the natural vibrational frequency to place it outside of the engine operating range.

The inner shroud which is relatively thick radially may have transverse notches 26 between adjacent slots for the purpose of weight reduction.

The use of this type of attachment is useful in combination with the spot welded outer end attachment shown .in the drawings. With the outer end of the vane supported by a foot, overlying and attached to the outer surface of the outer shroud, a semi-rigid or damped type of fastening at the inner end, as shown, equalizes the load between the inner and outer shrouds and still avoids the localized stressing that would result from a rigid attachment at both ends. It also'prevents excessive wear on the inner end of the vane where it engages the shroud which occurred when a radially loose attachment was used between the inner shroud and the inner ends of the .vanes.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

I claim:

1. In a stator construction, an outer vane supporting shroud, a substantially concentric inner vane supporting shroud, a row of vanes extending between said shrouds and having ends supported by said shrouds, substantially radial slots in one of said shrouds to receive the vane ends radially slidable therein, and spring pins extending in an axial direction through said one of said shrouds and engaging the vane ends in said shroud for holding the vanes in position, each spring pin including a sleeve of resilient material having an axially extending slot therein, each of said vanes being rigidly secured to the other shroud to prevent radial movement with respect thereto.

2. In a stator construction, an outer vane supporting shroud, a substantially concentric inner vane support- 3 ingsl rrpud, a row of vanes extending between said shrouds and having ends supported by said shrouds, one end of each vane having a foot engaging with the side of one shroud opposite to the other shroud, said other shroud having substantially radial slots therein to receive the vaneends slidably therein and springpins extending in an axial direction through the slotted shrouds and en a ing the vane ends in said slotted shroud for holding the vanes in position, each spring pin including a sleeve of resilient material having an axially-extending slot therein.

3. In a stator construction, an outer vane supporting shroud, a substantially concentric inner vane supporting shroud, a row of vanes extending between said shrouds and having ,ends supported by said shrouds, one end of each vane having a foot engaging with the side of one shroud opposite to the other shroud, said other shroud having substantially radial slots therein to receive the vane ends slidably therein, and axially extending openings intersecting said slots, and pins in said axial openings in said other shroud to hold the vanes in position therein, each pin including a sleeve of resilient material having an axially extending slot therein to provide a resilient attachment.

4. In a stator construction, an outer vane supporting shroud, a substantially concentric inner vane supporting shroud, a row of vanes extending between said shrouds, one of said shrouds having substantially radial slots therein and the vanes having ends'substantially the shape of and slidably received in said slots, each of said slots having at least one straight side and each of said vanes having a similar straight side extending transversely of the shroud, said straight sides having cooperating grooves therein extending transversely of the shroud to form a substantially cylindrical opening and a spring pin in the opening formed by said cooperating grooves, each pin including .a sleeve of resilient material having an axially extending slot therein to provide a resilient attachment.

5. In a stator construction, spaced outer and inner concentric shrouds, a row of vanes extending between said shrouds and supported by said shrouds, one of said shrouds having substantially radial openings therein to receive the ends of the vanes slidably therein, each of said openings having parallel side walls and the vane ends therein having similar parallel side walls engaging with the side Walls of the slot, transverse openings in said shrouds extending parallel to said side walls and lying in part in the side wall of the opening and in part in the side walls of the vane ends, and spring pins in said transverse openings to retain the vanes in position in said shroud, each pin including a sleeve of resilientmaterial having an axially extending slot therein to provide a resilient attachment.

6. In a stator construction, spaced outer and inner concentric shrouds, a row of vanes extending between said shrouds and supported by said shrouds, each vane having a foot on the outer end engaging with the outer surface of the outer shroud, each of said shrouds having openings through which the vanes extend, each vane hav= ing an inner vane end having parallel side walls, and the cooperating opening in the inner shroud being substantially radial and having cooperating parallel side walls engaging with the side walls of the slot, transverse openings in said shrouds extending parallel to said side walls and lying in part in the side walls of the opening and in part in the side wallsof the vane ends to form a circular opening, and substantially cylindrical spring pins in said circular openings to retain the vanes in position in said inner shroud, each spring pin being radially resilient to provide a resilient attachment between the vane and the shroud.

7. In a stator construction, spaced inner and outer concentric shroud rings, a row of vanes extending be tween said shroud rings and supported by said shrouds, each shroud having substantially radial openings therein through which the vanes extend, each vane having at its outer end anintegral foot overlying the outer shroud and rigidly attached thereto, each vane having at its inner end anv integral enlargement slidably fitting in the associated opening in the inner shroud, each enlargement and the associated opening having cooperating, transversely extending fiat surfaces, said cooperating surfaces havingopposed grooves therein defining a transverse opening, and a spring pin in said opening, each spring pin being resilient radially of the pin to provide a resilient attachment for the inner end of the vane.

References Cited in the file of this patent UNITED STATES PATENTS 

